Fix cache configuration for case sensitive filesystems like ext4

The cache config `BlackHole` should be replaced to `Black-Hole` so the filename-inflector will map the name to the camelCase version.

```
Fatal error: Uncaught exception 'Zend_Cache_Exception' with message 'file Zend/Cache/Backend/Blackhole.php not found in include_path' in /home/bcremer/www/shopware4/engine/Library/Zend/Cache.php on line 209

Zend_Cache_Exception: file Zend/Cache/Backend/Blackhole.php not found in include_path in /home/bcremer/www/shopware4/engine/Library/Zend/Cache.php on line 209

Call Stack:
    0.0005     229544   1. {main}() /home/bcremer/www/ShopwareCLI/sw:0
    0.0462     884488   2. Enlight_Bootstrap->loadResource() /home/bcremer/www/ShopwareCLI/sw:68
```